Logging: full AppHandle Debug dump on every line of transcribe_audio (≈96% of log size)

[MaximAndreevich]

Description

The transcribe_audio span includes app: AppHandle without skip, so every event inside it
prints the full AppHandle Debug output (~9 KB: Tauri config, CSP, plugin list, state TypeIds...).
Combined with per-chunk INFO logging during resampling (Processing chunk N /
Successfully resampled chunk N, 818 lines for one 14-min file), a single transcription attempt
produced a 7.7 MB log: 950 lines, 837 of them with the dump. Without the dumps it's 322 KB.

Suggested:

• #[instrument(skip(app))] on transcribe_audio (and any other command taking AppHandle).
• Per-chunk progress at DEBUG/TRACE, or one progress line per N%.
• Minor: daily log files are named cap-desktop.log.2026-09-28; macOS doesn't treat them as
  logs (no Console.app double-click). RollingFileAppender::builder().filename_suffix("log")
  would give cap-desktop.2026-09-28.log.
• Minor: System audio dropping frames WARN is repeated every 5 s even when the drop counter
  hasn't changed.

Additional Context

• Cap version: 0.6.0
• Operating system, version: 26.2 (25C56)
• Device (optional): Macbook M1

cap-desktop-2.log

[linear]

CAP-829

[avinash-git-24]

Hi @Brendonovich @richiemcilroy, I looked into this log bloat issue in apps/desktop/src-tauri/src/.

Because transcribe_audio uses #[instrument] without skip(app), tracing serializes tauri::AppHandle's Debug implementation (~9 KB of Tauri config, CSP, and state TypeIds) into the span fields and repeats it on every inner log event—including the per-chunk resampling info! calls.

Proposed fix plan:

1. Add #[instrument(skip(app))] to transcribe_audio (and audit other #[instrument] Tauri commands in apps/desktop/src-tauri/src/ taking AppHandle).
2. Lower the per-chunk resampling log lines (Processing chunk N / Successfully resampled chunk N) from info! to debug!/trace! while keeping high-level transcription lifecycle logs at info!.
3. Update RollingFileAppender::builder() to use .filename_prefix("cap-desktop").filename_suffix("log") so rotated logs end in .log (cap-desktop.YYYY-MM-DD.log) for macOS Console.app compatibility.

Happy to take this on and submit a PR if that sounds good!